Micro perforated foils are used in specific acoustic panels. The acoustic panels provide a sound absorbing effect based on Helmholtz resonant sound absorption when the micro perforated foils are used in combination with a space behind the micro perforated foil. Such acoustic panels are, for example, discussed in “Micro-Perforated Structures as Sound Absorbers—A review and Outlook”, by Helmut V. Fuchs, Xueqin Zha, published in Acta Acustica united with Acustica, Volume 92, No 1, January 2006, pp 13-146. The micro perforated foil is a foil in which a plurality of relatively small holes is provided. When two micro perforated foils are used, the two foils have to be separated from each other by a spacing structure. The spacing structure is arranged to provide an air gap between the micro perforated foils. Relatively large panels may be created by combining a spacing structure that extends along a relatively large area with two micro perforated foils on both sides of the spacing structure. If the micro perforated foils are transparent or translucent, and the spacing structures do not obstruct the light, light may be transmitted through the acoustic panel, which results in an optical acoustic panel. The optical acoustic panel may be provided at any location in rooms or relatively large open spaces such that sound is absorbed and such that light emitted by a light emitter, or light received via a window, is not obstructed by the optical acoustic panel.
Although the known optical acoustic panels provide a relatively good sound absorption and provide a relatively good light transmission, the person present in the space in which the optical acoustic panel is provided mainly benefits from the acoustic characteristics of the optical acoustic panel compared to a situation without an optical acoustic panel. The optical characteristics of the optical acoustic panel influence the lighting conditions in the space to a limited extent.
Especially when the space in which the optical acoustic panel is provided does not contain windows through which daylight is received, the well-being of people who are frequently in the space is not positively influenced by the lighting conditions in the space. There is a need for means which influence the lighting conditions such that the persons, who are available in the space, experience the lighting conditions of the space as a lighting condition which is comparable to a situation in which daylight was received via a window or a skylight.